The present invention relates to the cabinet-making art and, more particularly, to a power-operated hand tool that can be used by the cabinetmaker or other craftsman to clamp a plurality of side-by-side boards into generally flat alignment with one another to form a wooden panel for use as a cabinet door or the like.
Wood panels used as cabinet doors and the like are typically constructed from a number of boards that are glued together edge-to-edge to form the complete panel. The panel may then be sanded or planed flat and milled out or routered to produce an aesthetically pleasing design on the front face of the panel.
Small cabinet-making shops typically lack a good way of forcing the boards into flat alignment with one another and holding them in such alignment while the panel is being squeezed from the sides by pipe clamps or the like until adhesive between edges of the boards sets up. Typically, cabinetmakers may have to use mallets to pound the boards into place while they adjust and readjust the pipe clamps at various locations along the length of the boards. It can be a slow, tedious, inexact, and sometimes frustrating procedure.
The present invention overcomes the problems of the prior art by providing a power-operated hand tool that the cabinetmaker or other craftsman can use to quickly and easily clamp the individual boards of the panel vertically into generally flat, horizontal alignment with one another during the panel-making process. With the boards clamped flat by the flattening tool, the craftsman can then use a pipe clamp adjacent the tool to squeeze the boards together horizontally so their edges are in tight, abutting engagement with one another. With the clamp tightened, the craftsman releases the flattening tool, withdraws it from the boards, and reinstalls it at a different location along their length if necessary. After the panel has been completely flattened and the boards are tightly held by the clamps, the flattening tool is removed and adhesive that has been applied to edges of the boards is allowed to cure.
In a preferred embodiment, the tool is designed for two-handed operation, having a handle portion that is gripped by both hands of the user so as to both stabilize the tool and keep both hands in a safe location during operation. One gripping element of the handle portion extends generally in a vertical plane and is disposed to be gripped by one hand of the operator. A second gripping element extends in a generally horizontal plane transverse to the first gripping element and is offset vertically therefrom in disposition to be gripped by the other hand of the user. A safety lock associated with the first gripping element is disposed within reach of the user""s index finger when he grasps the first gripping element so as to release the lock and permit actuation of a valve in the vicinity of the second gripping element. The valve is so disposed that when the user""s other hand is engaged with the second gripping element, the index finger and thumb can shift the valve to its opened position, allowing pressurized air to actuate an air cylinder associated with the clamping portion of the tool.
The clamping portion of the tool includes a pair of opposed jaws that are shifted relative to one another by the air cylinder. In a preferred embodiment, the lower jaw is fixed, while the upper jaw is moveable, being supported by the piston rod of the air cylinder for movement toward and away from the fixed jaw. Preferably, the two jaws are in the nature of elongated, parallel bars that are relatively narrow and which are adapted to extend transversely across the boards, with the lower jaw beneath the boards and the upper jaw above the boards, during use. To facilitate reception of the boards into the space between the two clamping bars, both bars have outboard, free ends that define an open entry mouth into the clamping zone. The tool is thus applied to the boards endwise as the open mouth receives the boards, and is similarly withdrawn endwise from the boards as they pass outwardly through the open mouth at the conclusion of the flattening procedure.
To facilitate use of the tool, in a preferred embodiment of the invention the boards are supported a short distance above a work surface by pipe clamps or other types of clamp devices. By supporting the boards in this way, a clearance space is defined beneath the boards that provides room for the lower jaw of the tool to slip into position beneath the boards when the tool is initially applied. Similarly, the lower jaw can be easily withdrawn from beneath the boards following actuation and release of the flattening jaws.